Musannaf Ibn Abi Shayba 23:106

Shababa ibn Sawwar narrated to us, he said: Layth ibn Sa'd narrated to us, from Yazid ibn Sinan, from Anas, from the Prophet (peace and blessings of Allah be upon him), he said: "There will be, before the Hour, tribulations like pieces of the dark night. A man will wake up in them as a believer and reach the evening as a disbeliever, and he will wake up as a disbeliever and reach the evening as a believer."